1. Field of the Invention
The invention relates to an industrial truck, in particular a forward-control counterweight fork-lift truck, having a liftable and tiltable load-lifting device, a traction drive, and operating drives for movement of the load-lifting device.
2. Technical Considerations
In the case of conventional industrial trucks, the operator has to estimate the weight of the load goods to be lifted (lifting load) and the height to which the load goods are to be lifted (lifting height). On the basis of this, the driving speed and the turning radius of the industrial truck must be set such that there is no tipping of the industrial truck to the front or to the side. Although this demanding task must be managed in a static or quasi-static operating range, i.e., an operating range having a relatively low driving speed, it is easily possible for this to be too much for the operator. When the load-bearing capacity of the industrial truck is exceeded or in the event of driving maneuvers which are not adapted to the current lifting load and lifting height, there is the risk of tipping accidents involving severe injury or death to the operator or nearby people, associated with a high level of damage to property. There has, therefore, been no shortage of thought given to creating suitable safety precautions for preventing accidents involving industrial trucks.
DE 29 09 667 C3, for example, has described a generic industrial truck providing intervention in the traction drive depending on the steering angle, the lifting height, and the load torque, and, in the process, the driving speed and, if necessary, also the (electromotive) braking deceleration are limited. This takes place by overriding the desired values predetermined by the operator, using correction signals from the control device.
The subject matter of EP 0 343 839 B1 is an industrial truck in which the driving speed is limited depending on the lifting load, the lifting height, the steering angle, and the direction of travel or the position of the center of gravity of the vehicle. In addition, provision is also made for limiting the acceleration of the industrial truck depending on the lifting height.
EP 1 078 878 A1 discloses the concept of limiting the tilting speed of an industrial-truck lifting mast depending on the lifting load and the lifting height.
Finally, EP 1 019 315 B1 discloses an industrial truck in which the driving speed is limited depending on the lifting load and the tilting angle, and a higher lowering speed without a load is made possible.
The present invention is based on the object of providing an industrial truck of the general type mentioned above but having further improved tipping stability.